The preparation of light-harvesting arrays requires the organization of a large number of pigments in well-defined 3-dimensional architectures. Porphyrinic macrocycles have been widely employed in the construction of synthetic light-harvesting arrays owing to their desirable optical and photochemical features, as well as the desire to mimic the properties of photosynthetic light-harvesting antennas (A. Burrell, et al., Chem. Rev. 101, 2751-2796 (2001)). A general limitation of porphyrins for light-harvesting purposes is that porphyrins have strong absorption only in the blue region (λmax ˜420 nm), with weak absorption across the remainder of the visible spectrum. One approach to increase the spectral coverage of porphyrin-based light-harvesting arrays has been to include accessory pigments that absorb in regions where the porphyrins are relatively transparent and which funnel the resulting excited-state energy to the porphyrin. The ideal accessory pigment for use with porphyrins should have the following properties: (1) strong light absorption in the region between the porphyrin Soret and Q bands, (2) a long-lived excited-state, (3) a high level of stability, (4) synthetic compatibility with a molecular building block approach, and (5) high solubility (R. Wagner and J. Lindsey, Pure Appl. Chem., 68, 1373-1380 (1998)) Accessory pigments that have been used with porphyrins include boron-dipyrrin dyes, (R. Wagner and J. Lindsey, J. Am. Chem. Soc., 116, 9759-9760 (1994); A. Ambroise, et al., Chem. Mater., 13, 1023-1034 (2001); F. Li, et al., J. Am. Chem. Soc., 120, 10001-10017 (1998); A. Ambroise, et al. J. Org. Chem., 67, 3811-3826 (2002)), carotenoids (D. Gust, et al., Acc. Chem. Res., 34, 40-48 (2001); D. Gust, et al., Acc. Chem. Res., 16, 198-205 (1993)), coumarin dyes (S. Hecht, et al., J. Am. Chem. Soc., 123, 18-25 (2001)), cyanine dyes (Lindsey, J., et al., Tetrahedron, 45, 4845-4866 (1989)), perylene-imide dyes (A. Ambroise, et al. J. Org. Chem., 67, 3811-3826 (2002); E. Just and M. Wasielewski, Superlattices Microstr., 28, 317-328 (2000); K.-Y. Tomizaki, et al., J. Org. Chem., 67, 6519-6534 (2002)), and xanthene dyes (J. Lindsey, et al., Tetrahedron, 50, 8941-8968 (1994)). Meeting all of the criteria for an ideal accessory pigment is a significant challenge and no one class is superior in all aspects. The carotenoids absorb very strongly but have very short excited-state lifetimes, requiring very close juxtaposition for energy transfer to an acceptor. The cyanine dyes can be tuned for absorption across the visible region, but like the xanthene dyes, are positively charged, limiting solubility and typically causing difficulties in purification. The coumarins are neutral but absorb weakly and the absorption band is in the vicinity of the porphyrin Soret band, affording little additional spectral coverage. The perylene-monoimide dyes have modest absorption intensity, undergo efficient energy transfer, and are non-polar, but require extensive substitution with bulky groups to achieve adequate solubility (J. Lindsey, et al., Tetrahedron, 50, 8941-8968 (1994); R. Loewe, et al., J. Mater. Chem., 12, 3438-3451 (2002)). The boron-dipyrrin dyes have been widely used as fluorescent labels (H. Kim, et al., Chem. Commun., 1889-1890 (1999); A. Burghart, et al., J. Org. Chem., 64, 7813-7819 (1999); J. Chen, et al., J. Org. Chem., 65, 2900-2906 (2000); A. Burghart, et al., Chem. Commun., 2203-2204 (2000)) in biological applications and provide a nice compromise of all features for use with porphyrins. While the synthesis of boron-dipyrrins is more straightforward than that of perylene-imides, the one type of boron-dipyrrin that was used in conjunction with porphyrins exhibited a short, biphasic excited-state lifetime, limiting the yield of energy transfer (F. Li, et al., J. Am. Chem. Soc., 120, 10001-10017 (1998)). Accordingly, there remains a need for new types of dyes that can be used as accessory pigments with porphyrins.